Hydraulic actuation to operate ultra-slow insertion velocities

Introduction 

The treatment of severe hearing loss with a cochlear implant requires the insertion of an electrode array (EA) into the inner ear. Automation of the EA insertion offers the opportunity to perform the insertion slower and more uniform than manually feasible. This promises a better protection of the delicate intracochlear structures which are essential for the residual hearing. While experimental studies in the laboratory and initial experience with robotic systems in patients support this hypothesis, it is not clear if many patients will be able to benefit from these advances, considering the additional resources needed to implement them.

Material and Methods 

Therefore, we developed a simple insertion tool (“Cochlea Hydro Drive”, CHD) for use of hydraulic actuation. A standard single-use syringe connected to an infusion pump enables the programmable forward-feed movement. A surgical retractor with a flexible arm was chosen to position the tool along a manually adjusted trajectory.

Results 

Insertion tests on artificial cochlea models confirmed the desired slow and smooth movement. Experiments with human skull specimens also demonstrated the intraoperative usability of the method including assembly and positioning of the CHD and the hydraulically actuated EA insertion. Digital volume tomography showed the correct alignment of the CHD to the basal turn of the cochlea as well as the proper placement of the ET.

Conclusion 

The CHD facilitates ultra-slow insertions and no movement amplitudes from involuntary muscle movements (e.g. tremors) are transmitted into the inner ear via the EA as the CHD is fixed during the whole insertion. Given its simple design and use of standard clinical materials, its clinical translation could reach a wide variety of clinical scenarios.

 

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Conflict of Interest

The author declares that there is no conflict of interest.

Publikationsverlauf

Artikel online veröffentlicht:
24. Mai 2022